Continuous lighting systems for gaseous-discharge lamps with incandescent lamps on standby

ABSTRACT

An improved continuous lighting system for gaseous-discharge lamps which provides immediate lighting of incandescent light facilities upon extinguishment of the gaseous-discharge lamp. The lighting system further provides a delay, after reignition of the gaseous-discharge lamp, to maintain the incandescent lights lit until the gaseous-discharge lamp warms up and reaches a predetermined intensity, then the incandescent lights are extinguished.

United States Patent [72] Inventor Carl R. Snyder Aliei, Tex.

[2]] Appl. No. 801,953

[22] Filed Feb. 25, I969 (45] Patented June I, 1971 [73] AssigneeEsquire, Inc.

[54] CONTINUOUS LIGHTING SYSTEMS FOR GASEOUS-DISCHARGE LAMPS WITHINCANDESCENT LAMPS 0N STANDBY 13 Claims, 12 Drawing Figs.

[52] U.S.Cl 315/91,

{SI} Int. Cl ..H 05b 39/10,

' l-IOSb 41/46 [50] Field otSearch 3l5/88,9l, 92

[56] References Cited UNITED STATES PATENTS I,970,519 8/1934 Dorgelo etal. 3 l 5/192X 2,043,023 6/1936 Westendorp 3 I 5/l 82X FOREIGN PATENTS377,937 5/1964 Switzerland Primary Examiner-Roy Lake AssistantExaminerPalmer C. Demeo Attorneys-Tom Arnold, Donald C. Roylance, WalterKruger,

Bill Durkee, F rank S. Vaden, Ill, Louis T. Pirkey and Stanley A. BecketABSTRACT: An improved continuous lighting system for gaseous-dischargelamps which provides immediate lighting of incandescent light facilitiesupon extinguishment of the gaseous-discharge lamp. The lighting systemfurther provides a delay, after reignition of the gaseous-dischargelamp, to maintain the incandescent lights lit until thegaseous-discharge lamp warms up and reaches a predetermined intensity,then the incandescent lights are extinguished.

A A A II A PATENTEIJJUN H9?! SHEET 1 UF 3 FIG. 2

m G 7 wAw SRC mfi C SM SU MC YR 2 w T mm Em M n U 6 mm in 5 I 2 |k Rn EUWC 0m PC 2 Carl R. Snyder INVENTOR BY M, Qor lame,

W & Um ATTORNEYS PATENTED JUN 1 1911 SHEET 2 (IF 3 l I 46 l F/G.4 I A iFIG. 8 4 l T GASEOUS 43 l DISCHARGE GASEOUS LAMP ON AND 1* DISCHARGE 9 hWARMED UP LAMP INCANDESCENT RE-lGN/TES l A LIGHT OFF INCANDESCENT LIGHTo/v FIG. 5 F /G. 9

FIG. 5 FIG. 10

GASEOUS l DSCHARGE fs c l l azz LAMP OFF 9 INCANDESCENT x y l n/ Mi- 1LIGHT ON UP INCANDESCENT l LIGHT ON l I A 50 44 50 44 FIG. 7 JL l FIG.I] -1..-

Carl R. Snyder INVENTOR BY Awful, 120 mm,

A TTORNEYS PATENTED JUN Hen snmanra Carl R. Snyder INVENTOR BY M, W,

Lu-3a 3r Uwdzee ATTORNEYS CONTINUOUS LIGHTING SYSTEMS FOR GASEOUS-DISCHARGE LAMPS WI'II-I INCANDESCENT LAMPS ON STANDBY BACKGROUND OF THEINVENTION This invention relates to an improvement in continuouslighting systems for gaseous-discharge lamps of the type disclosed inUS. Pat. No. 3,5I7,254 entitled Continuous Lighting System forGaseous-Discharge Lamps with Incandescent Lights for Standby" by AlbertC. McNamara, .Ir., issued June 23 I970 and assigned to the sameassignee.

Gaseous-discharge lamps, such as mercury vapor and othermetallic-additive vapor lamps, have long been employedin industriallighting situations because of their extremely high'efficiency whencompared to other sources, such as incandescent lights. Agaseous-discharge lamp is a source of radiant energy characterized bythe emission of radiationfrom a stream of ionized vapor carrying currentbetween electrodes in the lamp. In starting the lamp, a relatively largevoltage is required. However, once current flows in thelamp, the lampexhibits a negative resistance characteristic. That is, the resistanceof the lamp decreases with an increase in current. Because of thischaracteristic, some form of current limiting device is necessary toprevent the destruction of the lamp once the lamp is started. Thiscurrent limiting device is called the ballast. Ballasts of complexstructures using inductive and capacitive reactances have been employedin AC circuits and have increased efficiencies when compared withresistive type ballasts. Ballasts may take the form of simple chokes,transformers, autotransformers, or a combination of these orotherstructures.

One of the most versatile and easiest to use of all gaseousdischargelamp ballasts is the regulator or lead type ballast. This ballast isalso sometimes referred to as the constant wattage type because itprovides constant wattage across the lamp, within specified fluctuationsof power line voltage. This makes the lead ballast particularlyadvantageous over other types of reactor or lag type ballasts. In usinga lead type ballast, the lamp voltage will lead the power line voltagebecause of the reactance in the ballast.

If a gaseous-discharge lamp is extinguished by a momentary power failureor by deliberate disconnection of the power supply, it cannot bereignited immediately. The lamp must cool down before it can bereignited. Thus, in many installations, it is desirable to have standbyor emergency lighting facilities to provide continuous lighting of anarea during the period when the gaseous-discharge lamp is not lit. Aftera gaseous-discharge lamp is reignited, it takes a period of time untilthe lamp fully warms up and reaches its maximum or operating brightnessor intensity. During this period, it may also be desirable to maintainthe emergency lighting facilities lit to provide sufficient lighting foran area until such time as the gaseous-discharge lamp provides thenecessary illumination whereupon the emergency lighting facilities canbe turned off. SUMMARY OF THE INVENTION The improved continuous lightingsystem utilizesthe lead ing lamp voltage provided by the lead ballastand includes facilities which are responsive to changes in the lampvoltage and the phase angle thereof for operating incandescent lightfacilities to provide continuous lighting during the period when agaseous-discharge lamp is extinguished. Additionally, the voltage andphase angle responsive facilities are suchthat the reignition of thegaseous-discharge lamp is sensed, but the extinguishment of theincandescent light facilities is delayed until the gaseous-dischargelamp has reached a. predetermined brightness or intensity whereupon theincandescent light facilities are turned off.

Specifically, the continuous lighting system includes a lead typeballast having a gaseous-discharge .lamp connected thereto. Incandescentlight facilities are connectedto the pri mary of the ballast and haveapower circuit connected-thereto for lighting the'incandescent lights. Atrigger circuit, which is responsive to the output of an integratorcircuit, renders the power circuit conductive. A bypass circuit isconnected to the integrator circuit and is responsive to a signal from asensing integrator which senses the gaseous-discharge lamp voltage andthe phase angle thereof. When the gaseous-discharge lamp is lit andfully warmed up, the voltage across the gaseousdischarge lamp leads thepower line or source voltage and the bypass circuit conducts on eachhalf cycle prior to the trigger circuit conducting. As long as thebypass circuit conducts first, the integrator will not be able totrigger the trigger circuit, thereby disabling the power circuit andpreventing the lighting of the incandescent lights. When there is amomentary power failure, the gaseous-discharge lamp voltage drops tozero and the lamp is extinguished. With power reapplied, there is a highvoltage applied to the extinguished gaseous-discharge lamp, but the lampcannot reignite until it cools. With the gaseousdischarge lampextinguished, the power line voltage and the lamp voltage are in phase.When these voltages are in phase, the trigger circuit takes less time tofire than the bypass circuit. At this point, the output from theintegrator circuit triggers the trigger circuit, which in turn rendersthe power circuit conductive to light the incandescent lights to providecontinuous lighting. When the gaseous-discharge lamp reignites, thevoltage across the lamp is low and is leading the power line voltage.This leading low voltage is sensed by the sensing integrator, but theoutput signal provided is insufficient to render the bypass circuitconductive prior to the power circuit conducting in each half cycle.This provides the delaying action desired to keep the incandescentlights lit during the period that the gaseous-discharge lamp isincreasing in brightness or intensity. The power circuit, once it isturned on, stays on until the end of each half cycle. Consequently, ifthe bypass circuit becomes conductive after the power circuit becomesconductive, the bypass circuit has no effect on the power circuit. Asthe gaseous-discharge lamp warms up, the leading voltage across the lampincreases in magnitude and is sensed by the sensing integrator. When theleading lamp voltage reaches a predetermined magnitude, the output fromthe sensing integrator renders the bypass circuit conductive at thebeginning of a half cycle before the power circuit conducts, and therebydisables the power circuit turning off the incandescent lights.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of atypical gaseous-discharge lamp fixture incorporating an embodiment ofthe present invention;

FIG. 2 is a block diagram of a continuous lighting system which embodiesthe principles of the present invention;

FIG. 3 is a detailed circuit diagram of the block diagram shown in FIG.2;

FIG. 4 is a wave diagram showing the power line voltage and theintegrator output voltage when the gaseous-discharge lamp is on andfully warmed up;

FIG. 5 is a wave diagram showing the lamp voltage and the sensingintegrator output voltage when the gaseous-discharge lamp is on andfully warmed up;

FIG. 6 is a wave diagram showing the power line voltage and theintegrator output voltage when the gaseous-discharge lamp isextinguished;

FIG. 7 is a wave diagram showing the lamp voltage and the sensingintegrator output voltage when the gaseous-discharge lamp isextinguished;

FIG. 8 is a wave diagram showing the power line voltage and theintegrator output voltage when the gaseous-discharge lamp reignites;

FIG. 9 is a wave diagram showing the lamp voltage and sensing integratoroutput voltage when the gaseous-discharge lamp reignites,

FIG. 10 is a wave diagram showing the power line voltage and theintegrator output voltage as the gaseous-discharge lamp'warms' up, butprior to its reaching its predetermined brightness;

FIG. 11 is a wave diagram showing the lamp voltage and the sensingintegrator output voltage as the gaseousdischarge lamp warms up, butprior to its reaching its predetermined brightness;

FIG. 12 is an alternative embodiment of the circuit shown in FIG. 3which includes a power circuit gate signal amplifier.

DESCRIPTION OF THE INVENTION Referring to FIG. 1, a gaseous-dischargelamp fixture is shown, such as might be used for lighting an outdoorarea, typically the entrance to a building or a parking lot. Fixture 10includes a shield 11 secured to a support post 12 by brackets 13 and 14in a conventional manner. Located within shield 11 is agaseous-discharge lamp 15, typically of the mercury-vapor type, and twoincandescent lights 16 and 17, which may be located at any place withinthe shield 11. Secured to the bottom of the shield 11 is a housing 18 inwhich the ballast and an electrical circuit in accordance with theinvention to be described herein is located. Appropriate leads or otherconnections connect lamp 15 and incandescent lights 16 and 17 to thecircuit within the housing 18. Appropriate power from an outside sourcemay be brought into the housing 18 through the hollow center of post 12.

Referring to FIG. 2, there is shown a block diagram wherein thegaseous-discharge lamp 15 is connected across a lead type generallydesignated as 21, which may be an autotransformer 23 and capacitor 25 asshown. Incandescent lights 16 and 17 are connected to the primary of theballast. A power circuit, generally designated as 24, is connected tothe incandescent lights 16 and 17. When the power circuit 24 isconductive, voltage is applied across the incandescent lights to lightthe lights. A trigger circuit, generally designated as 26, is connectedto the power circuit 24 and renders the power circuit 24 conductive inresponse to an output signal from an integrator circuit generallydesignated as 27. A bypass circuit, generally designated as 28 isconnected to the integrator circuit 27. When the bypass circuit 28 isconductive, integrator circuit 27 is prevented from triggering thetrigger circuit 26, thereby disabling power circuit 24 so that novoltage is applied to the incandescent lights 16 and 17. The bypasscircuit 28 is rendered conductive in response to an output signal from asensing integrator circuit, generally designated as 29, which senses thevoltage across the gaseous-discharge lamp 15 and the phase anglethereof.

In operation, assume that the gaseous-discharge lamp 15 is lit and theincandescent lights 16 and 17 are extinguished. In this state, thesensing integrator 29 determines that the voltage across thegaseous-discharge lamp 15 is of a certain magnitude and leads the sourcevoltage thereby rendering the bypass circuit 2 conductive. This preventsintegrator circuit 27 from triggering trigger circuit 26. Consequently,the power circuit 24 is not conductive and the incandescent lights 16and 17 are off. Upon interruption of the power, either due to amomentary power failure or to a deliberate disconnection of the power,the voltage across gaseous-discharge lamp 15 drops to zero and thegaseous-discharge lamp 15 is extinguished. With power reapplied, thevoltage applied to the gaseous-discharge lamp 15 is now high, but is inphase with the power line voltage. At this point, since the triggercircuit 26 takes less time to fire than the bypass circuit 28, theoutput from integrator 27 triggers the trigger circuit 26, before the bypass circuit conducts, which in turn renders the power circuit 24conductive thereby applying a voltage across the incandescent lights 17and 17 to provide continuous lighting.

After the power is reapplied, the voltage across the lamp 15 increasesto a rather high value, however, the lamp will not light until it cools.When the gaseous-discharge lamp 15 has cooled sufficiently to reignite,the voltage across the lamp 15, goes from a high voltage. This lowvoltage while sensed by the sensing integrator 29, is insufiicient totrigger the bypass circuit 28 before the trigger circuit 26 becomesconductive. Consequently, the power circuit 24 is still conductive andvoltage is applied to the incandescent lights 16 and 17. As thegaseous-discharge lamp 15 warms up, the voltage across the lampincreases. This increased leading voltage is sensed by the sensingintegrator 29, and when it reaches a predetermined magnitude triggersthe bypass circuit 28 before trigger circuit 26 and thereby effectivelydisables the power circuit 24 extinguishing the incandescent lights 16and 17. Thus, a delay is provided so that the incandescent lights 16 and17 remain on after the gaseous-discharge lamp 15 reignites until suchtime as the gaseous-discharge lamp 15 reaches a predetermined intensity.At this point, the incandescent lights 16 and 17 are no longer needed toprovide sufficient lighting, and they are extinguished.

Referring now to FIG. 3, there is shown a circuit diagram including anautotransformer 23 and a capacitor 25, which comprise the lead typeballast 21, connected to a voltage supply 31. Connected to the primaryof the ballast 21 are the incandescent lights 16 and 17. The powercircuit 24, which is connected in series with the incandescent lights 16and 17 and the voltage source 31, includes a triac 32 having its gateelectrode connected to a bilateral switch 33 which is trigger circuit26. A bilateral switch is a device that conducts or fires when apredetermined threshold voltage is reached for either the positive orthe negative half-cycles. A triac is a gated bilateral switch. While thecircuit herein is described with reference to triacs and bilateralswitches, it is to be understood that many modifications may be made inaccordance with the principles of this invention using gated or ungated,bilateral or unilateral switches. The integrator circuit 27 includes aresistor 34 and a capacitor 36 which applies an output to the bilateralswitch 33. Connected across the capacitor 36 is the bypass circuit 28which includes a triac 37 having its gate electrode connected to anotherbilateral switch 38. Bilateral switch 38 is serially connected to aresistor 39. The sensing integrator 29 includes a voltage dividerdesignated as 41 connected by a movable contact to resistor 39. Acapacitor 42 is connected to the resistor 39 across a portion of thevoltage divider 41.

In operation, assume again that the gaseous-discharge lamp 15 is lit andthe incandescent lights 16 and 17 are extinguished. When there is amomentary interruption of the voltage source 31, gaseous-discharge lamp15 is extinguished. Immediately prior to the extinguishment of thegaseousdischarge lamp 15, the voltage across the lamp was sufficientlyhigh and leading the line voltage so that bilateral switch 33 wasrendered conductive thereby triggering triac 37 so that the bypasscircuit 28 was conductive to prevent voltage from being applied acrossthe incandescent lights 16 and 17 through the power circuit 24. it is tobe noted that when using a lead type ballast 23, such as autotransformer23, and capacitor 25, the voltage across the gaseous-discharge lamp 15leads the power line voltage or source voltage during the time thegaseous-discharge lamp 15 is on, because of the reactive values of theballast 21 and capacitor 25. Further, it is noted that with this sameballast, with the discharge lamp extinguished the voltage applied to itis in phase with the power line voltage. The values of the resistor 34and the voltage divider 41 and the capacitors 36 and 42 are chosen suchthat, when the gaseous-discharge lamp 15 is on and fully warmed up ittakes less time to reach the threshold voltage of switch 38 than ittakes to reach the threshold voltage of switch 33 so that bypass occurs.Conversely, when the gaseous-discharge lamp 15 is extinguished (in thecooling state) it takes more time to reach the threshold voltage ofswitch 38 than it takes to reach the threshold voltage of switch 33,therefore, there is no bypass and the power circuit is conductive.

After the voltage source 31 is turned on again, the gaseousdischargelamp 15 remaining extinguished until it cools sufficiently, voltage isapplied across resistor 34 and to capacitor 36 and when the charge onthe capacitor 36 builds up sufficiently, which takes place early in eachhalf cycle, it reaches the threshold level of bilateral switch 33rendering the switch and 17 to immediately light those lights. Duringthe time that the gaseoustdischarge lamp is cooling the incandescentlights 16 and 17 remain lit. The nature of a triac is such that once itis triggered it stays conductive until it turns itself off at the end ofeach half cycle. Thus with a 60 Hz. supply, incan- 5 descent lamps l7and I7 turn on 120 times per second, or each half cycle. When thegaseous-discharge lamp 15 has cooled sufficiently so that it reignitesthere is a leading low voltage developed across the lamp. This leadinglow voltage insufficient to render the bilateral switch 38 conductive.Thus I gered before switch 33, it triggers triac 37 which renders thebypass circuit conductive. Bearing in mind the nature of a triac andthat the lamp voltage leads the power line voltage, once triac 37 istriggered before triac 32, the bypass circuit is conductive each halfcycle and prevents the power circuit from applying a voltage across theincandescent lights 16 and 2 17. This operation is described more fullywhen considered in conjunction with the descriptions of FIG. 4 throughll. As long as the gaseous-discharge lamp I5 is lit after warming up,the triac 37 is conductive each half cycle thereby disabling the powercircuit and leaving the incandescent lights 16 and I7 extinguished.

Referring now to FIGS. 4 through 11, there are shown wave diagrams forvarious operating conditions of the gaseousdischarge lamp illustratingthe operation of the system. The dotted lines 43 indicate the thresholdvoltage necessary to fire the bilateral switch 33, and the dotted lines44 indicate the threshold voltage necessary to fire the bilateral switch38. The AC power line voltage as it varies with time is indicated byline 46. The AC lamp voltage, or the voltage applied to the gase'Qua-discharge lamp I5, as it varies with time is indicated by line 50.Note that the lamp voltage 50 leads the power line voltage 46 when thegaseous-discharge lamp I5 is lit because of the lead type ballast 21.The output voltage from integrator 27 as it varies with time isindicated by line 47, and the output voltage from the sensing integrator29 as it varies with time is indicated by line 49.

In FIGS. 4 and 5, the gaseous-dishcarge lamp 15 is lit, and theincandescent lights 16 and 17 are extinguished. As long as thegaseous-discharge lamp 15 is lit, the lamp voltage leads 50 the powerline voltage 46 by angle theta, and the output voltage 49 from thesensing integrator 29 is sufficient to fire the bilateral switch 38, asshown at trigger point 51, which in turn triggers triac 37 to conduct,rendering the bypass circuit 28 conductive. The bypass circuit 28 drainscurrent from the integrator 27 preventing the capacitor 36 from chargingsuffrciently to fire switch 33. FIG. 4 illustrates that the outputvoltage 47 from integrator 27 is below the threshold voltage 43.Consequently, switch does not fire triac 32 is not triggered and thusthe power circuit 24 is nonconductive leaving the incandescent lights 16and 117 off.

FIGS. 6 and 7, the power has been momentarily turned off extinguishingthe gaseous-discharge lamp I5. It is to be noted here that the lampvoltage 50 is now in phase with the power line voltage 46. Thegaseous-discharge lamp l5 has not been reignited at this point.Immediately upon extinguishment of gaseous-discharge lamp 15, sinceintegrator 27 has a faster charge up time than integrator 29, thevoltage 47 reaches threshold voltage 43 and the bilateral switch 33 istriggered FIGS. 8 and 9 illustrate the condition where thegaseousdischarge lamp has reignited, but has not warmed up to itspredetermined brightness. Note that immediately upon ignition, the lampvoltage 50 leads the power line voltage 46 by angle theta. However, thelamp voltage 50 is just building up, and since integrator 27 charges upfaster than integrator 29, voltage 47 reaches threshold 43 beforevoltage 49 reaches threshold 44. Thus, the incandescent lights 16 and 17remain lit after the gaseous-discharge lamp has reignited. It isunderstood, of course, that once triac 32 is conducting, it remainsconductive until the end of the half cycle. Therefore, as long asvoltage 47 reaches its threshold 43 before voltage 49 reaches itsthreshold 44, the incandescent lights stay lit. This provides thedelaying action of the system. Different component having differentthreshold values can be selected to give any desired delay. Mostadvantageously, however, a delay will be chosen which is sufficient forthe gaseousdischarge lamp to substantially reach its operating ormaximum brightness or intensity, while not exceeding the primaryoperating current.

FIGS. 10 and I1 show the condition where the gaseousdischarge lamp I5has warmed up even further, although still not to its predeterminedbrightness. It can readily be seen that since the lamp voltage 50 leadsthe power line voltage 46, and is substantially a square wave, thevoltage 49 will soon reach its threshold 44 before voltage 47 reachesits threshold 43. When this occurs, the bypass circuit 24 becomesconductive and the incandescent lights 16 and 17 are extinguished asdescribed with reference to FIGS. 4 and 5.

FIG. 12 shows an alternative embodiment of the circuit shown in FIG. 3which includes a gate signal amplifier 52 connected between the powercircuit 24 and the trigger circuit 26. The gate signal amplifierincludes a triac 53 having one terminal connected to the power circuittriac 32 and the other terminal connected to a parallel combination of aresistor 54 and a capacitor 56. The gate of triac 53 is connected to thebilateral switch 33. This added amplifier circuit 52 reduces the gatingpower loss and provides a high gating current to the power circuit triac32.

It is to be understood that the above described embodiments are merelyillustrative of an application of the principles of this invention andthat numerous other arrangements and modifications may be made withinthe spirit and scope of the invention.

What I claim is:

l. A continuous lighting system comprising:

a gaseous-discharge lamp;

lead ballast means connected to said gaseous-discharge lamp;

an AC voltage source connected to said ballast means to ignite andoperate said gaseous-discharge lamp; incandescent light means; and

control means responsive to the extinguishment of said gaseous-dischargelamp for lighting said incandescent light means, said control meansfurther responsive to the magnitude of the voltage across thegaseous-discharge lamp and the phase difference between said lampvoltage and said AC source voltage for extinguishing said incandescentlight means after the gaseous-discharge lamp reignites and reaches apredetermined intensity.

2. A continuous lighting system comprising:

a gaseous-discharge lamp;

lead ballast means connected to said gaseous-discharge lamp;

an AC voltage source connected to said ballast means to ignite andoperate said gaseous-discharge lamp; incandescent light means;

first switch means responsive to a first predetermined voltage forlighting said incandescent light means;

first integrator circuit means having an input connected to said voltagesource and an output connected to said first switch means;

second integrator circuit means having an input connected to saidgaseous discharge lamp and an output; and

second switch means responsive to the output of said second integratorcircuit means having a second predetermined voltage and phase angle forpreventing said output from said first integrator circuit from reachingsaid first predetermined voltage.

3. A continuous lighting system comprising:

a gaseous-discharge lamp;

lead ballast means connected to said gaseous-discharge lamp;

an AC voltage source connected to said ballast means to ignite andoperate said gaseous-discharge lamp;

incandescent light means;

first circuit means responsive to the source voltage and the voltageacross the gaseous-discharge lamp being in phase for lighting saidincandescent light means; and

second circuit means responsive to the voltage across thegaseous-discharge lamp reaching a predetermined magnitude and leadingthe source voltage for disabling said first circuit means to extinguishsaid incandescent light means.

4. A continuous lighting system as described in claim 3 wherein saidfirst circuit means includes:

first gated switch means connected in series with said incandescentlight means and said voltage source;

first integrator circuit means having an input connected to said voltagesource and an output, and

second switch means responsive to a predetermined output from said firstintegrator circuit means for applying a gating voltage to said firstgated switch means to light said incandescent light means.

5. A continuous lighting system as described in claim 4 ineluding:

means for amplifying the gating voltage applied to said first gatedswitch means.

6. A continuous lighting system as described in claim 3 wherein saidsecond circuit means includes:

second integrator means having am input connected to saidgaseous-discharge lamp and an output; and

bypass circuit means responsive to an output from said second integratormeans of a predetermined magnitude and phase angle for disabling saidfirst circuit means.

7. A continuous lighting system as described in claim 1 wherein saidcontrol means includes:

first gated bilateral switch means connected in series with saidincandescent light means and said voltage source;

a first resistance and a first capacitance forming a first seriescombination, said first series combination connected in parallel acrosssaid first gated bilateral switch means;

second bilateral switch means connecting the gate electrode of saidfirst gated bilateral switch means with the juncture of said firstresistance and said first capacitance;

a voltage divider means connected across said gaseousdischarge lamp;

third gated bilateral switch means connected across said firstcapacitance;

fourth bilateral switch means connected to the gate electrode of saidthird gated bilateral switch means;

a second resistance and a second capacitance connected in series withsaid fourth bilateral switch means; and

means for connecting the juncture of said second resistance and saidsecond capacitance to a preselected point on said voltage divider means.

8. A continuous lighting system comprising:

a gaseous-discharge lamp;

lead ballast means connected to said gaseous-discharge lamp;

power means for applying an AC voltage to said ballast means to igniteand operate said gaseous-discharge lamp;

incandescent light means;

first circuit means responsive to a first voltage for applying voltagefrom said power means to said incandescent light means;

second circuit means, connected to said gaseous-discharge lamp and saidfirst circuit means, responsive to a second voltage greater than andleading said first voltage for disabling said first circuit means toextinguish said incandescent light means, said second leading voltagebeing applied when said gaseous-discharge lamp is lit and has 5 reacheda predetermined intensity.

9. A continuous lighting system as described in claim 8 wherein saidfirst circuit means includes:

first gated bilateral switch means connected in series with saidincandescent light means and said power means;

' first integrator circuit means having an input connected to said powermeans and an output; and second bilateral switch means connecting thegate electrode of said first gated bilateral switch means with theoutput of said first integrator circuit means.

10. A continuous lighting system as described in claim 8 wherein saidsecond circuit means includes:

second integrator circuit means having an input connected to saidgaseousdischarge lamp and an output; and

bypass circuit means responsive to an output from said second integratormeans of a predetermined magnitude and phase angle for disabling saidfirst circuit means.

11. A continuous lighting system as described in claim 10 wherein saidbypass circuit means includes:

third gated bilateral switch means connected to disable said firstintegrator circuit means when conductive; and

fourth bilateral switch means responsive to the output of said secondintegrator circuit means for applying a gate voltage to said third gatedbilateral switch means.

12. A continuous lighting system comprising:

a gaseous-discharge lamp;

lead ballast means connected to said gaseous-discharge lamp;

power means for applying an AC voltage to said ballast means to igniteand operate said gaseous-discharge lamp;

incandescent light means;

first circuit means, connected to said incandescent light means,responsive to a first trigger voltage for applying voltage from saidpower means to said incandescent light means;

second circuit means, connected to said gaseous-discharge lamp and saidfirst circuit means, said second circuit means normally being conductiveand providing a voltage bypass from said first circuit means when saidgaseousdischarge lamp is operating at a predetermined intensitypreventing said first trigger voltage from being applied to said firstcircuit means, said second circuit means being nonconductive in responseto the extinguishment of said gaseous-discharge lamp to permit saidfirst trigger voltage to be applied to said first circuit means to lightsaid incandescent light means, said incandescent light means remaininglit until said second circuit means conducts in response to thegaseous-discharge lamp reigniting and reaching a predeterminedintensity.

13. A continuous lighting system comprising a gaseous-discharge lamp;

lead ballast means connected to said gaseous-discharge lamp;

an AC voltage source;

incandescent light means;

a power circuit connected in series with said incandescent light meansand said voltage source, said power circuit rendered conductive inresponse to a gating voltage;

a trigger circuit for applying said gating voltage to said power circuitin response to a predetermined threshold voltage;

an integrator circuit having an input connected to said voltage sourceand an output connected to said trigger circuit;

a sensing circuit having an input connected to said gaseousdischargelamp and an output; and

a bypass circuit connected to the output of said sensing circuit; saidby pass circuit conducting when said gaseous discharge lamp is lit andoperating at a predetermined ingaseous-discharge lamp is extinguished topermit said integrator circuit to apply the predetermined thresholdvoltage to said trigger circuit to enable said power circuit to lightsaid incandescent light means.

" UNXTED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,5,7 Dated June 1, 1971 Inventofls) Carl R, Snvder It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 3, line 26, after "type" should be inserted -ba11ast; line 52,"2" should read -28;'

line 66, "17" should read l6-; line 72, after "high voltage" should beinserted --value"to a low voltage value and leads the line voltage.;Column lfline 19, "it" should read -It--g. .v Column 5, line 2,"gaseoustdischarge" should read -gaseousdischarge-; line 6, after lamps,"17" should read -l6--; line 10, before "insufficient" should beinserted -is--; line 59, before "switch" should be inserted --33; line63, before "FIGS." should be inserted -In--; Column 6, line 15,"component" should read -components-p' M Column 9, line 1,. "bypass"should read --from-. l,

Signed and seaELed this 22nd day of February 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Patents

1. A continuous lighting system comprising: a gaseous-discharge lamp;lead ballast means connected to said gaseous-discharge lamp; an ACvoltage source connected to said ballast means to ignite and operatesaid gaseous-discharge lamp; incandescent light means; and control meansresponsive to the extinguishment of said gaseousdischarge lamp forlighting said incandescent light means, said control means furtherresponsive to the magnitude of the voltage across the gaseous-dischargelamp and the phase difference between said lamp voltage and said ACsource voltage for extinguishing said incandescent light means after thegaseous-discharge lamp reignites and reaches a predetermined intensity.2. A continuous lighting system comprising: a gaseous-discharge lamp;lead ballast means connected to said gaseous-discharge lamp; an ACvoltage source connected to said ballast means to ignite and operatesaid gaseous-discharge lamp; incandescent light means; first switchmeans responsive to a first predetermined voltage for lighting saidincandescent light means; first integrator circuit means having an inputconnected to said voltage source and an output connected to said firstswitch means; second integrator circuit means having an input connectedto said gaseous discharge lamp and an output; and second switch meansresponsive to the output of said second integrator circuit means havinga second predetermined voltage and phase angle for preventing saidoutput from said first integrator circuit from reaching said firstpredetermined voltage.
 3. A continuous lighting system comprising: agaseous-discharge lamp; lead ballast means connected to saidgaseous-discharge lamp; an AC voltage source connected to said ballastmeans to ignite and operate said gaseous-discharge lamp; incandescentlight means; first circuit means responsive to the source voltage andthe voltage across the gaseous-discharge lamp being in phase forlighting said incandescent light means; and second circuit meansresponsive to the voltage across the gaseous-discharge lamp reaching apredetermined magnitude and leading the source voltage for disablingsaid first circuit means to extinguish said incandescent light means. 4.A continuous lighting system as described in claim 3 wherein said firstcircuit means includes: first gated switch means connected in serieswith said incandescent light means and said voltage source; firstintegrator circuit means having an input connected to said voltagesource and an output, and second switch means responsive to apredetermined output from said first integrator circuit means forapplying a gating voltage to said first gated switch means to light saidincandescent light means.
 5. A continuous lighting system as describedin claim 4 including: means for amplifying the gating voltage applied tosaid first gated switch means.
 6. A continuous lighting system asdescribed in claim 3 wherein said second circuit means includes: secondintegrator means having am input connected to said gaseous-dischargelamp and an output; and bypass circuit means responsive to an outputfrom said second integrator means of a predetermined magnitude and phaseangle for disabling said first Circuit means.
 7. A continuous lightingsystem as described in claim 1 wherein said control means includes:first gated bilateral switch means connected in series with saidincandescent light means and said voltage source; a first resistance anda first capacitance forming a first series combination, said firstseries combination connected in parallel across said first gatedbilateral switch means; second bilateral switch means connecting thegate electrode of said first gated bilateral switch means with thejuncture of said first resistance and said first capacitance; a voltagedivider means connected across said gaseous-discharge lamp; third gatedbilateral switch means connected across said first capacitance; fourthbilateral switch means connected to the gate electrode of said thirdgated bilateral switch means; a second resistance and a secondcapacitance connected in series with said fourth bilateral switch means;and means for connecting the juncture of said second resistance and saidsecond capacitance to a preselected point on said voltage divider means.8. A continuous lighting system comprising: a gaseous-discharge lamp;lead ballast means connected to said gaseous-discharge lamp; power meansfor applying an AC voltage to said ballast means to ignite and operatesaid gaseous-discharge lamp; incandescent light means; first circuitmeans responsive to a first voltage for applying voltage from said powermeans to said incandescent light means; second circuit means, connectedto said gaseous-discharge lamp and said first circuit means, responsiveto a second voltage greater than and leading said first voltage fordisabling said first circuit means to extinguish said incandescent lightmeans, said second leading voltage being applied when saidgaseous-discharge lamp is lit and has reached a predetermined intensity.9. A continuous lighting system as described in claim 8 wherein saidfirst circuit means includes: first gated bilateral switch meansconnected in series with said incandescent light means and said powermeans; first integrator circuit means having an input connected to saidpower means and an output; and second bilateral switch means connectingthe gate electrode of said first gated bilateral switch means with theoutput of said first integrator circuit means.
 10. A continuous lightingsystem as described in claim 8 wherein said second circuit meansincludes: second integrator circuit means having an input connected tosaid gaseous-discharge lamp and an output; and bypass circuit meansresponsive to an output from said second integrator means of apredetermined magnitude and phase angle for disabling said first circuitmeans.
 11. A continuous lighting system as described in claim 10 whereinsaid bypass circuit means includes: third gated bilateral switch meansconnected to disable said first integrator circuit means whenconductive; and fourth bilateral switch means responsive to the outputof said second integrator circuit means for applying a gate voltage tosaid third gated bilateral switch means.
 12. A continuous lightingsystem comprising: a gaseous-discharge lamp; lead ballast meansconnected to said gaseous-discharge lamp; power means for applying an ACvoltage to said ballast means to ignite and operate saidgaseous-discharge lamp; incandescent light means; first circuit means,connected to said incandescent light means, responsive to a firsttrigger voltage for applying voltage from said power means to saidincandescent light means; second circuit means, connected to saidgaseous-discharge lamp and said first circuit means, said second circuitmeans normally being conductive and providing a voltage bypass from saidfirst circuit means when said gaseous-discharge lamp is operating at apredetermined intensity preventing said first trigger voltage from beingapplied to Said first circuit means, said second circuit means beingnonconductive in response to the extinguishment of saidgaseous-discharge lamp to permit said first trigger voltage to beapplied to said first circuit means to light said incandescent lightmeans, said incandescent light means remaining lit until said secondcircuit means conducts in response to the gaseous-discharge lampreigniting and reaching a predetermined intensity.
 13. A continuouslighting system comprising a gaseous-discharge lamp; lead ballast meansconnected to said gaseous-discharge lamp; an AC voltage source;incandescent light means; a power circuit connected in series with saidincandescent light means and said voltage source, said power circuitrendered conductive in response to a gating voltage; a trigger circuitfor applying said gating voltage to said power circuit in response to apredetermined threshold voltage; an integrator circuit having an inputconnected to said voltage source and an output connected to said triggercircuit; a sensing circuit having an input connected to saidgaseous-discharge lamp and an output; and a bypass circuit connected tothe output of said sensing circuit; said by pass circuit conducting whensaid gaseous discharge lamp is lit and operating at a predeterminedintensity to prevent said integrator circuit bypass applying thepredetermined threshold voltage to said trigger circuit; said bypasscircuit being nonconductive in response to the output of said sensingcircuit indicating that the gaseous-discharge lamp is extinguished topermit said integrator circuit to apply the predetermined thresholdvoltage to said trigger circuit to enable said power circuit to lightsaid incandescent light means.